The present invention concerns improved fuel compositions. More particularly, it relates to diesel fuel compositions having improved wear resistance.
Internal combustion engines are susceptible to wear in the upper cylinder region. It is believed that the majority of wear occurring in the upper cylinder is caused by the upward motion of the piston. While lubricating oils prevent wear on the downward stroke, the lubricating oil has limited or essentially no contact with the cylinder wall on the upward motion. During the upward compression stroke, particularly in diesel engines, the fuel is in contact with the cylinder wall and can influence its wear.
Accordingly, it is an object of the invention to provide diesel fuel having improved antiwear properties.
It is known that terpene derivatives of 2,5-dimercapto-1,3,4-thiadiazole impart antioxidant and antiwear properties to lubricating oils as described in U.S. patent application Ser. No. 041,496 filed Apr. 23, 1987.
It has been now discovered that terpene dervatives of 2,5-dimercapto-1,3,4-thiadiazole impart antiwear properties to diesel fuel.